It was narrated from Anas that Umm Sulaim asked the Messenger of Allah (ﷺ) about a woman who sees in her dream something like a man sees. He said:
"If water is released then let her perform Ghusl." (JA)
English reference (JA): Vol. 1, Book 1, Hadith 195 (JA)
Arabic reference (JA): Book 1, Hadith 196 (JA)